Abstract

Mobile Ad-hoc Network (MANET) is a collection of mobile devices dynamically forming a communication network without any centralized control and pre-existing network infrastructure. Due to the presence of mobility in the MANET, the interconnections between stations are likely to change on a continual basis, resulting in frequent changes of network topology. Consequently, routing becomes a vital factor and a major challenge in such a network. In this paper to study the impact of four Internet Engineering Task Force (IETF) standardized routing protocols on MANETs and thereby comprehensively analyzes their performance under varying network sizes and node mobility rates. The four routing protocols that are considered in the analysis are Optimized Link State Routing (OLSR), Ad-hoc On-demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Temporally Ordered Routing Algorithm (TORA). In addition, from a transport layer’s perspective, it is necessary to consider Transmission Control Protocol (TCP) as well for MANETs because of its wide application, which enjoys the advantage of reliable data transmission in the Internet. However, the factors such as scalability and mobility cause TCP to suffer from a number of severe performance problems in an ad-hoc environment. Hence, it is an importance to identify the most suitable and efficient TCP variants that can robustly perform under these specific conditions. In this paper evaluate the performance of three TCP variants under a variety of network conditions. The simulations results reveal that out of the three, the Selective Acknowledgement (SACK) variant can adapt relatively well to the changing network sizes while the Reno performs most robustly in different mobility scenarios. On the other hand, the research asserts the fact of superiority of proactive protocol, over reactive and hybrid ones when routing the same traffic in the network. The reactive protocols AODV performance has been found to be remarkable.